Azo dye and process of making same.



bro/790,364.

UNITED STATES Patented May 23, 1905.

' PATENT OFFICE.

JOHN HAGENBAOI-I, OF BASEL, S INITZERLAND, ASSIGNOR TO ANILINE COLOUR AND EXTRAOT- WORKS, FORMERLY JOHN H. GEIGY, OF

BASEL, SWITZERLAND.

AZO DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 790,364, dated May 23, 1905.

Application filed November 1, 1904. Serial No. 231,083.

1 '0 M whom it may concern:

Be it known that 1, JOHN HAGnNBAoH. Ph. D. a citizen of the Swiss Repu blic, residing at Basel, Switzerland, have invented certain new and useful Improvements in Azo Compounds and Processes of Making Same, of which the following is a specification.

The invention relates to the manufacture of new azo dyes of the naphthalene series, very soluble in water, by sulfonation of the oxyazo dyes obtained by combination of diazonaphtholsulfo -acids with naphthol. These dyestuffs yield on wool dyed in the usual manner and subsequently treated with chromic compounds blue-black shades of very valuable properties.

The coloring-matter obtained by copulation of the l-diazo-Q-naphthol-4c-sulfonic acid resp. of its anhydrid with beta naphthol dyes wool when after-treated with chrome in blue-black shades of remarkable fastness; but on account of its insufficient solubility in acetic-acid solution its application for dyeing in apparatus causes some difiiculties. In order to bring this coloring-matter into a more soluble form, 1 have tried to transform it into a sulfonic acid by action of concentrated sulfuric acid, and I have found that when avoiding too high temperatures, which cause the decomposition of the coloring matter, the sulfonation can be accomplished very easily by aid of concentrated sulfuric acid, especially when mixed with a certain proportion of anhydrous sulfuric acid. The thus obtained new coloring-matter is extremely soluble in water, but shows, nevertheless, the same excellent solidity against milling and potting as the original coloring-matter. Besides the advantage of the remarkable solubility the new coloring-matter possesses all p the same good qualities of the starting stufl.

l- :liazo-2-naphthol-4-sulfonic acid with betanaphthol precipitated from its alkaline solution by the addition of acetic acid dried and powdered is slowly introduced while stirring into three parts of monohydrate of sulfuric acid at about 30 to L0 centigrade. The coloring-matter partly dissolves. Partly it turns into small needles of a greenish metallic luster. ring one part of fuming sulfuric acid, (containing twenty five per cent. anhydrid,) whereupon the mixture becomes thin and the temperature rises up to to centigrade. The stirring is continued at this temperature till a test is well soluble in cold water. The mixture is then poured into ice-water, precipitated with kitchen-salt, filtered off, washed with a diluted solution of common salt, dried, and powdered.

The thus-obtained coloring-matter forms a dark powder of a greenish metallic luster easily soluble in cold water with a raspberryred color, turning into a pure blue by addition. of ammonia. By concentrated hydrochloric acid the solution is precipitated in brownishviolet flocks. In concentrated sulfuric acid. the coloring-matter dissolves with a dark-blue shade. On wool it yields in an acetic-acid bath a brownish-red shade, turninginto a blueblack when treated after dyeing with chromium compounds and into a violet-black with copper salts.

Having now described my invention, what I claim is- 1. The process of making monoazo dyes, very soluble in water, consisting in the sulfonation of azo dyestuflis obtained by combination of the anhydrids of diazo naphtholsulfonic acids with naphthol.

2. The process of making a monoazo dye, very soluble in water, consisting in the sulfonation of the azo dyestuif obtained by combination of the anhydrid of 1-diazo-2-naphtl1ol-4-sulfonic acid with beta-naphthol.

3. As a new article of manufacture, the monoazo dye which results by sulfonation of the azo dyestuff obtained by combination of the.

anhydrid of 1-diazo-2-naphthol- I-sulfo-acid Then I add slowly while constantly stir- I with beta-naphthol, forming a dark powder ing with chromium compounds and into a vioof a greenish metallic luster, easily soluble in let-black with copper salts. cold Water with a raspberry-red color turn- In testimony whereofI have signed my name ing into a pure blue by addition of ammonia, to this specification in the presence of two sub- 5 soluble in concentrated sulfuric acid with a scribing witnesses.

dark-blue shade, precipitated by concentrated hydrochloric acid from the alkaline solution JOHN HAGENBAOH' in brownish-violet flocks and yielding on wool Vitnesses: in acetic-acid bath brownish-red shades, turn- Guo. GIFFORD,

1O ing into a blue-black when treated after dye- ALBERT GRAcnER. 

